Reversible immobilization of engineered molecules by Ni-NTA chelators

Biosensors based on gold nanoelectrode ensembles and screen printed electrodes

“…The effectiveness of this proccess is confirmed by observing the trend of the oxidation peak (centered at around þ800 mV) that decreases after few scans of CV. As already reported in the case of Au and graphite traditional SPE [35], this behaviour is due to the rapid deposition of CYS till the saturation of the electrode surface [35]. Chronoamperometric measurements gave a maximum oxidation current response which is two orders of magnitude lower than in the case of CYS deposed on Au screen printed probes.…”

“…The electrochemical deposition of CYS has been demonstrated to be effective on pure gold electrode as well as on screen printed Au-graphite [35]. This treatment left on the top surface free available amine groups.…”

“…The PANI/NEE/SPS was immersed in a solution of 10% v/v APTES for 90 min, in order to obtain a terminal amino group (-NH 2 ) onto the PC surface [35,37]. The resulting derivative was accurately washed with PB solution (pH 6.8) and water.…”

“…Taking into account the declared pore density of the template membrane (which corresponds approximately to the Au nanodisks density in the NEE) and the area of a single nanodisk (declared pore diameter of 30 nm or measured [45] as about 50 nm in a previous paper by SEM), active areas can be calculated for conventional NEE and for NEE/SPS. Table 1 summarizes the result of the comparison among three different gold probes: -gold electrodes obtained by galvanic deposition of Au on copper paths with a rugosity factor of 1.13 as previously described [35], -gold NEE produced according to [31] and modified in [38], -gold NEE/SPS prepared with our method. 4.0e-7…”

“…Polyaniline (PANI) was electrochemically deposed by cycling the electrode potential from À0.4 to þ1.0 V of 50 mM aniline in diluted sulphuric acid (0.5 M), as extensively reported in literature [35,36]. The working electrode obtained, constituted by polyaniline wires grown in the gold discs is now named PANI/NEE/SPS.…”